triage: fix extract_plist livecheck label

This label was never being applied because the regex only matched `strategy :extract_plist` when indented by 2 spaces, this is always at least 4 spaces because it is nested inside of a `livecheck do` block. The newline check shouldn't be necessary regardless, and removing it causes this to also match in the case that the `livecheck` is nested within another block, ie. `on_arm do`.

.github/workflows/triage.yml

@@ -72,7 +72,7 @@ jobs:
 
             - label: extract_plist livecheck
               path: Casks/.+
-              content: \n  strategy :extract_plist.*\n
+              content: strategy :extract_plist
 
             - label: missing zap
               path: Casks/.+